Initial version

1 files changed, 23 insertions, 0 deletions

diff --git a/src/unistd/nice.c b/src/unistd/nice.c
new file mode 100644
index 0000000..1c2295f
--- /dev/null
+++ b/src/unistd/nice.c
@@ -0,0 +1,23 @@
+#include <unistd.h>
+#include <errno.h>
+#include <sys/resource.h>
+#include <limits.h>
+#include "syscall.h"
+
+int nice(int inc)
+{
+	int prio = inc;
+	// Only query old priority if it can affect the result.
+	// This also avoids issues with integer overflow.
+	if (inc > -2*NZERO && inc < 2*NZERO)
+		prio += getpriority(PRIO_PROCESS, 0);
+	if (prio > NZERO-1) prio = NZERO-1;
+	if (prio < -NZERO) prio = -NZERO;
+	if (setpriority(PRIO_PROCESS, 0, prio)) {
+		if (errno == EACCES)
+			errno = EPERM;
+		return -1;
+	} else {
+		return prio;
+	}
+}